A gas turbine, typically called a ‘jet’ engine, was introduced by Frank Whittle in the 1930s. The gas turbine is an internal combustion engine. In the internal combustion engine, air is compressed, fuel added, the mixture ignited, and the rapid expansion of the resultant hot gas produces the power. The combustion in a jet engine is continuous and its power results from expanding gas being forced out of the rear of the engine. The expanding gas flow is an action which creates a reaction of equivalent force or thrust. The thrust is transmitted through the engine to the aircraft, propelling it through the air.
The gas turbine includes three main sections: a compressor section, a combustion section; and a turbine section. The compressor section draws air into the engine, pressurizes it, and delivers it to the combustion chamber. The combustion chamber receives air from the compressor section and mixes the air with fuel sprayed from nozzles in the front of the chamber. The mixture is burned at temperatures up to 2000° C. to generate the maximum possible heat energy. The turbine section extracts energy from the hot exhaust gases to drive the compressor section.
The compressor section includes a low-pressure compressor and a high pressure compressor. Each compressor includes a plurality of discs which are bolted together to form a rotor. Rotor blades are mounted on the rotor. The turbine section includes a low-pressure turbine and a high pressure turbine. Like each compressor, each turbine includes a plurality of discs which are bolted together to form a rotor. Rotor blades are mounted on the rotor. Each compressor is driven from a respective turbine by a single shaft.
Prior to assembly, various characteristics of each disc are measured and used as inputs to a software program that provides optimal assembly information for each rotor based on the measured characteristics. The compressor section or turbine section is then assembled accordingly. After each compressor section and turbine section is assembled, various characteristics of each compressor and turbine are measured and used as inputs to a software program that provides optimal assembly information for the gas turbine (whole engine) based on the measured characteristics. The gas turbine/engine is then assembled accordingly. Example software programs for assembling engines include: “ShaftMate™” by Axiam, Incorporated of Gloucester, Mass.